Non-local Muscle Fatigue Effects on Muscle Strength, Power, and Endurance in Healthy Individuals: A Systematic Review with Meta-analysis

Abstract

Background The fatigue of a muscle or muscle group can produce global responses to a variety of systems (i.e., cardiovascular, endocrine, and others). There are also reported strength and endurance impairments of non-exercised muscles following the fatigue of another muscle; however, the literature is inconsistent. Objective To examine whether non-local muscle fatigue (NLMF) occurs following the performance of a fatiguing bout of exercise of a different muscle(s). Design Systematic review and meta-analysis. Search and Inclusion A systematic literature search using a Boolean search strategy was conducted with PubMed, SPORT-Discus, Web of Science, and Google Scholar in April 2020, and was supplemented with additional 'snowballing' searches up to September 2020. To be included in our analysis, studies had to include at least one intentional performance measure (i.e., strength, endurance, or power), which if reduced could be considered evidence of muscle fatigue, and also had to include the implementation of a fatiguing protocol to a location (i.e., limb or limbs) that differed to those for which performance was measured. We excluded studies that measured only mechanistic variables such as electromyographic activity, or spinal/ supraspinal excitability. After search and screening, 52 studies were eligible for inclusion including 57 groups of participants (median sample = 11) and a total of 303 participants. ResultsThe main multilevel meta-analysis model including all effects sizes (278 across 50 clusters [median = 4, range = 1 to 18 effects per cluster) revealed a trivial point estimate with high precision for the interval estimate [− 0.02 (95% CIs = − 0.14 to 0.09)], yet with substantial heterogeneity (Q (277) = 642.3, p < 0.01), I 2 = 67.4%). Subgroup and meta-regression analyses showed that NLMF effects were not moderated by study design (between vs. within-participant), homologous vs. heterologous effects, upper or lower body effects, participant training status, sex, age, the time of post-fatigue protocol measurement, or the severity of the fatigue protocol. However, there did appear to be an effect of type of outcome measure where both strength [0.11 (95% CIs = 0.01-0.21)] and power outcomes had trivial effects [− 0.01 (95% CIs = − 0.24 to 0.22)], whereas endurance outcomes showed moderate albeit imprecise effects [− 0.54 (95% CIs = − 0.95 to − 0.14)]. Conclusions Overall, the findings do not support the existence of a general NLMF effect; however, when examining specific types of performance outcomes, there may be an effect specifically upon endurance-based outcomes (i.e., time to task failure). However, there are relatively fewer studies that have examined endurance effects or mechanisms explaining this possible effect, in addition to fewer studies including women or younger and older participants, and considering causal effects of prior training history through the use of longitudinal intervention study designs. Thus, it seems pertinent that future research on NLMF effects should be redirected towards these ...

The impact of postexercise blood flow restriction on local muscle endurance of a remote limb

“…Other studies have demonstrated that maintained ischaemia does not alter the maximal force output of the contralateral limb (Kennedy et al, 2013, 2015; Pethick et al, 2018). It would be reasonable that sustained activation of group III/IV afferents would have a larger impact on the submaximal performance of nonexercised muscles as nonlocal muscle fatigue has been suggested to play a larger role with limiting local muscle endurance rather than maximal force production (Behm et al, 2021; Halperin et al, 2015). Therefore, the purpose of the present study was to test whether maintaining activation of group III/IV muscle afferents via restricting blood flow postexercise would negatively impact local muscle endurance on a nonexercised limb.…”

Crossover fatigue after unilateral submaximal eccentric contractions of the knee flexors involves peripheral alterations and perceived fatigue

“…This reduced muscle force production de ned as performance fatigability 1 is commonly attributed to interactions between peripheral and central factors including impairments of contractile function distal to the neuromuscular junction and adjustments within the central nervous system at the spinal and/or the supraspinal level 2 .Interestingly, during maximal or fatiguing unilateral contractions, involuntary increased electromyographic activity and force production are observed in the non-exercised contralateral homologous muscle 3,4 . In addition, after a fatiguing unilateral exercise, performance fatigability can occur in the non-exercised contralateral muscle, but this observation is still disputed in the literature 5 .…”

“…Although evidenced many times 4,7−11 , some studies failed 12,13 to report crossover fatigue. A recent systematic review with meta-analysis 5 concluded that the con icting literature neither supports the existence of crossover fatigue nor "non-local muscle fatigue" (i.e., fatigue occurring in any non-exercised heterologous muscle).…”

“…In crossover fatigue studies, the performance fatigability of the contralateral homologous muscle is generally assumed to encompass complex fatigue-induced central adjustments 20,21 possibly leading to reduced central drive to the non-exercised muscle 7,9−11 . In addition, peripheral factors involving the dispersion of metabolites through the cardiovascular system and/or the presence of heat shock proteins in resting muscles have been assumed to account for the decreased performance of the non-exercised contralateral muscle 5,20 As far as we know, only one study reported an impairment of the resting electrically evoked twitch associated with reduced performance of the contralateral rst dorsal interosseous muscle 4 . Finally, subjective sensations such as pain, effort or increased perception of fatigue could also contribute to the altered performance of the contralateral homologous muscle 5,8,9,20 , even though such measures were scarcely performed in crossover fatigue studies 8 .…”

“…Finally, subjective sensations such as pain, effort or increased perception of fatigue could also contribute to the altered performance of the contralateral homologous muscle 5,8,9,20 , even though such measures were scarcely performed in crossover fatigue studies 8 . Consequently, even if the underlying mechanisms accounting for crossover fatigue are still debated, it has recently been proposed that a complex interaction between peripheral and central factors associated with increased subjective sensations is likely to occur 5 . This suggestion is in accordance with some of the results reported in the two crossover fatigue studies using unilateral eccentric exercise 8,9 , although these two studies were not included in the meta-analysis.…”